<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Date Helpers
 *
 * @package        CodeIgniter
 * @subpackage    Helpers
 * @category    Helpers
 * @author        EllisLab Dev Team
 * @link        https://codeigniter.com/user_guide/helpers/date_helper.html
 */

// ------------------------------------------------------------------------

if (!function_exists('now')) {
    /**
     * Get "now" time
     *
     * Returns time() based on the timezone parameter or on the
     * "time_reference" setting
     *
     * @param    string
     * @return    int
     */
    function now($timezone = NULL)
    {
        if (empty($timezone)) {
            $timezone = config_item('time_reference');
        }

        if ($timezone === 'local' OR $timezone === date_default_timezone_get()) {
            return time();
        }

        $datetime = new DateTime('now', new DateTimeZone($timezone));
        sscanf($datetime->format('j-n-Y G:i:s'), '%d-%d-%d %d:%d:%d', $day, $month, $year, $hour, $minute, $second);

        return mktime($hour, $minute, $second, $month, $day, $year);
    }
}

// ------------------------------------------------------------------------

if (!function_exists('mdate')) {
    /**
     * Convert MySQL Style Datecodes
     *
     * This function is identical to PHPs date() function,
     * except that it allows date codes to be formatted using
     * the MySQL style, where each code letter is preceded
     * with a percent sign:  %Y %m %d etc...
     *
     * The benefit of doing dates this way is that you don't
     * have to worry about escaping your text letters that
     * match the date codes.
     *
     * @param    string
     * @param    int
     * @return    int
     */
    function mdate($datestr = '', $time = '')
    {
        if ($datestr === '') {
            return '';
        } elseif (empty($time)) {
            $time = now();
        }

        $datestr = str_replace(
            '%\\',
            '',
            preg_replace('/([a-z]+?){1}/i', '\\\\\\1', $datestr)
        );

        return date($datestr, $time);
    }
}

// ------------------------------------------------------------------------

if (!function_exists('standard_date')) {
    /**
     * Standard Date
     *
     * Returns a date formatted according to the submitted standard.
     *
     * As of PHP 5.2, the DateTime extension provides constants that
     * serve for the exact same purpose and are used with date().
     *
     * @todo    Remove in version 3.1+.
     * @deprecated    3.0.0    Use PHP's native date() instead.
     * @link    http://www.php.net/manual/en/class.datetime.php#datetime.constants.types
     *
     * @example    date(DATE_RFC822, now()); // default
     * @example    date(DATE_W3C, $time); // a different format and time
     *
     * @param    string $fmt = 'DATE_RFC822'    the chosen format
     * @param    int $time = NULL        Unix timestamp
     * @return    string
     */
    function standard_date($fmt = 'DATE_RFC822', $time = NULL)
    {
        if (empty($time)) {
            $time = now();
        }

        // Procedural style pre-defined constants from the DateTime extension
        if (strpos($fmt, 'DATE_') !== 0 OR defined($fmt) === FALSE) {
            return FALSE;
        }

        return date(constant($fmt), $time);
    }
}

// ------------------------------------------------------------------------

if (!function_exists('timespan')) {
    /**
     * Timespan
     *
     * Returns a span of seconds in this format:
     *    10 days 14 hours 36 minutes 47 seconds
     *
     * @param    int    a number of seconds
     * @param    int    Unix timestamp
     * @param    int    a number of display units
     * @return    string
     */
    function timespan($seconds = 1, $time = '', $units = 7)
    {
        $CI =& get_instance();
        $CI->lang->load('date');

        is_numeric($seconds) OR $seconds = 1;
        is_numeric($time) OR $time = time();
        is_numeric($units) OR $units = 7;

        $seconds = ($time <= $seconds) ? 1 : $time - $seconds;

        $str = array();
        $years = floor($seconds / 31557600);

        if ($years > 0) {
            $str[] = $years . ' ' . $CI->lang->line($years > 1 ? 'date_years' : 'date_year');
        }

        $seconds -= $years * 31557600;
        $months = floor($seconds / 2629743);

        if (count($str) < $units && ($years > 0 OR $months > 0)) {
            if ($months > 0) {
                $str[] = $months . ' ' . $CI->lang->line($months > 1 ? 'date_months' : 'date_month');
            }

            $seconds -= $months * 2629743;
        }

        $weeks = floor($seconds / 604800);

        if (count($str) < $units && ($years > 0 OR $months > 0 OR $weeks > 0)) {
            if ($weeks > 0) {
                $str[] = $weeks . ' ' . $CI->lang->line($weeks > 1 ? 'date_weeks' : 'date_week');
            }

            $seconds -= $weeks * 604800;
        }

        $days = floor($seconds / 86400);

        if (count($str) < $units && ($months > 0 OR $weeks > 0 OR $days > 0)) {
            if ($days > 0) {
                $str[] = $days . ' ' . $CI->lang->line($days > 1 ? 'date_days' : 'date_day');
            }

            $seconds -= $days * 86400;
        }

        $hours = floor($seconds / 3600);

        if (count($str) < $units && ($days > 0 OR $hours > 0)) {
            if ($hours > 0) {
                $str[] = $hours . ' ' . $CI->lang->line($hours > 1 ? 'date_hours' : 'date_hour');
            }

            $seconds -= $hours * 3600;
        }

        $minutes = floor($seconds / 60);

        if (count($str) < $units && ($days > 0 OR $hours > 0 OR $minutes > 0)) {
            if ($minutes > 0) {
                $str[] = $minutes . ' ' . $CI->lang->line($minutes > 1 ? 'date_minutes' : 'date_minute');
            }

            $seconds -= $minutes * 60;
        }

        if (count($str) === 0) {
            $str[] = $seconds . ' ' . $CI->lang->line($seconds > 1 ? 'date_seconds' : 'date_second');
        }

        return implode(', ', $str);
    }
}

// ------------------------------------------------------------------------

if (!function_exists('days_in_month')) {
    /**
     * Number of days in a month
     *
     * Takes a month/year as input and returns the number of days
     * for the given month/year. Takes leap years into consideration.
     *
     * @param    int    a numeric month
     * @param    int    a numeric year
     * @return    int
     */
    function days_in_month($month = 0, $year = '')
    {
        if ($month < 1 OR $month > 12) {
            return 0;
        } elseif (!is_numeric($year) OR strlen($year) !== 4) {
            $year = date('Y');
        }

        if (defined('CAL_GREGORIAN')) {
            return cal_days_in_month(CAL_GREGORIAN, $month, $year);
        }

        if ($year >= 1970) {
            return (int)date('t', mktime(12, 0, 0, $month, 1, $year));
        }

        if ($month == 2) {
            if ($year % 400 === 0 OR ($year % 4 === 0 && $year % 100 !== 0)) {
                return 29;
            }
        }

        $days_in_month = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
        return $days_in_month[$month - 1];
    }
}

// ------------------------------------------------------------------------

if (!function_exists('local_to_gmt')) {
    /**
     * Converts a local Unix timestamp to GMT
     *
     * @param    int    Unix timestamp
     * @return    int
     */
    function local_to_gmt($time = '')
    {
        if ($time === '') {
            $time = time();
        }

        return mktime(
            gmdate('G', $time),
            gmdate('i', $time),
            gmdate('s', $time),
            gmdate('n', $time),
            gmdate('j', $time),
            gmdate('Y', $time)
        );
    }
}

// ------------------------------------------------------------------------

if (!function_exists('gmt_to_local')) {
    /**
     * Converts GMT time to a localized value
     *
     * Takes a Unix timestamp (in GMT) as input, and returns
     * at the local value based on the timezone and DST setting
     * submitted
     *
     * @param    int    Unix timestamp
     * @param    string    timezone
     * @param    bool    whether DST is active
     * @return    int
     */
    function gmt_to_local($time = '', $timezone = 'UTC', $dst = FALSE)
    {
        if ($time === '') {
            return now();
        }

        $time += timezones($timezone) * 3600;

        return ($dst === TRUE) ? $time + 3600 : $time;
    }
}

// ------------------------------------------------------------------------

if (!function_exists('mysql_to_unix')) {
    /**
     * Converts a MySQL Timestamp to Unix
     *
     * @param    int    MySQL timestamp YYYY-MM-DD HH:MM:SS
     * @return    int    Unix timstamp
     */
    function mysql_to_unix($time = '')
    {
        // We'll remove certain characters for backward compatibility
        // since the formatting changed with MySQL 4.1
        // YYYY-MM-DD HH:MM:SS

        $time = str_replace(array('-', ':', ' '), '', $time);

        // YYYYMMDDHHMMSS
        return mktime(
            substr($time, 8, 2),
            substr($time, 10, 2),
            substr($time, 12, 2),
            substr($time, 4, 2),
            substr($time, 6, 2),
            substr($time, 0, 4)
        );
    }
}

// ------------------------------------------------------------------------

if (!function_exists('unix_to_human')) {
    /**
     * Unix to "Human"
     *
     * Formats Unix timestamp to the following prototype: 2006-08-21 11:35 PM
     *
     * @param    int    Unix timestamp
     * @param    bool    whether to show seconds
     * @param    string    format: us or euro
     * @return    string
     */
    function unix_to_human($time = '', $seconds = FALSE, $fmt = 'us')
    {
        $r = date('Y', $time) . '-' . date('m', $time) . '-' . date('d', $time) . ' ';

        if ($fmt === 'us') {
            $r .= date('h', $time) . ':' . date('i', $time);
        } else {
            $r .= date('H', $time) . ':' . date('i', $time);
        }

        if ($seconds) {
            $r .= ':' . date('s', $time);
        }

        if ($fmt === 'us') {
            return $r . ' ' . date('A', $time);
        }

        return $r;
    }
}

// ------------------------------------------------------------------------

if (!function_exists('human_to_unix')) {
    /**
     * Convert "human" date to GMT
     *
     * Reverses the above process
     *
     * @param    string    format: us or euro
     * @return    int
     */
    function human_to_unix($datestr = '')
    {
        if ($datestr === '') {
            return FALSE;
        }

        $datestr = preg_replace('/\040+/', ' ', trim($datestr));

        if (!preg_match('/^(\d{2}|\d{4})\-[0-9]{1,2}\-[0-9]{1,2}\s[0-9]{1,2}:[0-9]{1,2}(?::[0-9]{1,2})?(?:\s[AP]M)?$/i', $datestr)) {
            return FALSE;
        }

        sscanf($datestr, '%d-%d-%d %s %s', $year, $month, $day, $time, $ampm);
        sscanf($time, '%d:%d:%d', $hour, $min, $sec);
        isset($sec) OR $sec = 0;

        if (isset($ampm)) {
            $ampm = strtolower($ampm);

            if ($ampm[0] === 'p' && $hour < 12) {
                $hour += 12;
            } elseif ($ampm[0] === 'a' && $hour === 12) {
                $hour = 0;
            }
        }

        return mktime($hour, $min, $sec, $month, $day, $year);
    }
}

// ------------------------------------------------------------------------

if (!function_exists('nice_date')) {
    /**
     * Turns many "reasonably-date-like" strings into something
     * that is actually useful. This only works for dates after unix epoch.
     *
     * @param    string    The terribly formatted date-like string
     * @param    string    Date format to return (same as php date function)
     * @return    string
     */
    function nice_date($bad_date = '', $format = FALSE)
    {
        if (empty($bad_date)) {
            return 'Unknown';
        } elseif (empty($format)) {
            $format = 'U';
        }

        // Date like: YYYYMM
        if (preg_match('/^\d{6}$/i', $bad_date)) {
            if (in_array(substr($bad_date, 0, 2), array('19', '20'))) {
                $year = substr($bad_date, 0, 4);
                $month = substr($bad_date, 4, 2);
            } else {
                $month = substr($bad_date, 0, 2);
                $year = substr($bad_date, 2, 4);
            }

            return date($format, strtotime($year . '-' . $month . '-01'));
        }

        // Date Like: YYYYMMDD
        if (preg_match('/^(\d{2})\d{2}(\d{4})$/i', $bad_date, $matches)) {
            return date($format, strtotime($matches[1] . '/01/' . $matches[2]));
        }

        // Date Like: MM-DD-YYYY __or__ M-D-YYYY (or anything in between)
        if (preg_match('/^(\d{1,2})-(\d{1,2})-(\d{4})$/i', $bad_date, $matches)) {
            return date($format, strtotime($matches[3] . '-' . $matches[1] . '-' . $matches[2]));
        }

        // Any other kind of string, when converted into UNIX time,
        // produces "0 seconds after epoc..." is probably bad...
        // return "Invalid Date".
        if (date('U', strtotime($bad_date)) === '0') {
            return 'Invalid Date';
        }

        // It's probably a valid-ish date format already
        return date($format, strtotime($bad_date));
    }
}

// ------------------------------------------------------------------------

if (!function_exists('timezone_menu')) {
    /**
     * Timezone Menu
     *
     * Generates a drop-down menu of timezones.
     *
     * @param    string    timezone
     * @param    string    classname
     * @param    string    menu name
     * @param    mixed    attributes
     * @return    string
     */
    function timezone_menu($default = 'UTC', $class = '', $name = 'timezones', $attributes = '')
    {
        $CI =& get_instance();
        $CI->lang->load('date');

        $default = ($default === 'GMT') ? 'UTC' : $default;

        $menu = '<select name="' . $name . '"';

        if ($class !== '') {
            $menu .= ' class="' . $class . '"';
        }

        $menu .= _stringify_attributes($attributes) . ">\n";

        foreach (timezones() as $key => $val) {
            $selected = ($default === $key) ? ' selected="selected"' : '';
            $menu .= '<option value="' . $key . '"' . $selected . '>' . $CI->lang->line($key) . "</option>\n";
        }

        return $menu . '</select>';
    }
}

// ------------------------------------------------------------------------

if (!function_exists('timezones')) {
    /**
     * Timezones
     *
     * Returns an array of timezones. This is a helper function
     * for various other ones in this library
     *
     * @param    string    timezone
     * @return    string
     */
    function timezones($tz = '')
    {
        // Note: Don't change the order of these even though
        // some items appear to be in the wrong order

        $zones = array(
            'UM12' => -12,
            'UM11' => -11,
            'UM10' => -10,
            'UM95' => -9.5,
            'UM9' => -9,
            'UM8' => -8,
            'UM7' => -7,
            'UM6' => -6,
            'UM5' => -5,
            'UM45' => -4.5,
            'UM4' => -4,
            'UM35' => -3.5,
            'UM3' => -3,
            'UM2' => -2,
            'UM1' => -1,
            'UTC' => 0,
            'UP1' => +1,
            'UP2' => +2,
            'UP3' => +3,
            'UP35' => +3.5,
            'UP4' => +4,
            'UP45' => +4.5,
            'UP5' => +5,
            'UP55' => +5.5,
            'UP575' => +5.75,
            'UP6' => +6,
            'UP65' => +6.5,
            'UP7' => +7,
            'UP8' => +8,
            'UP875' => +8.75,
            'UP9' => +9,
            'UP95' => +9.5,
            'UP10' => +10,
            'UP105' => +10.5,
            'UP11' => +11,
            'UP115' => +11.5,
            'UP12' => +12,
            'UP1275' => +12.75,
            'UP13' => +13,
            'UP14' => +14
        );

        if ($tz === '') {
            return $zones;
        }

        return isset($zones[$tz]) ? $zones[$tz] : 0;
    }
}

// ------------------------------------------------------------------------

if (!function_exists('date_range')) {
    /**
     * Date range
     *
     * Returns a list of dates within a specified period.
     *
     * @param    int    unix_start    UNIX timestamp of period start date
     * @param    int    unix_end|days    UNIX timestamp of period end date
     *                    or interval in days.
     * @param    mixed    is_unix        Specifies whether the second parameter
     *                    is a UNIX timestamp or a day interval
     *                     - TRUE or 'unix' for a timestamp
     *                     - FALSE or 'days' for an interval
     * @param    string  date_format    Output date format, same as in date()
     * @return    array
     */
    function date_range($unix_start = '', $mixed = '', $is_unix = TRUE, $format = 'Y-m-d')
    {
        if ($unix_start == '' OR $mixed == '' OR $format == '') {
            return FALSE;
        }

        $is_unix = !(!$is_unix OR $is_unix === 'days');

        // Validate input and try strtotime() on invalid timestamps/intervals, just in case
        if ((!ctype_digit((string)$unix_start) && ($unix_start = @strtotime($unix_start)) === FALSE)
            OR (!ctype_digit((string)$mixed) && ($is_unix === FALSE OR ($mixed = @strtotime($mixed)) === FALSE))
            OR ($is_unix === TRUE && $mixed < $unix_start)
        ) {
            return FALSE;
        }

        if ($is_unix && ($unix_start == $mixed OR date($format, $unix_start) === date($format, $mixed))) {
            return array(date($format, $unix_start));
        }

        $range = array();

        $from = new DateTime();
        $from->setTimestamp($unix_start);

        if ($is_unix) {
            $arg = new DateTime();
            $arg->setTimestamp($mixed);
        } else {
            $arg = (int)$mixed;
        }

        $period = new DatePeriod($from, new DateInterval('P1D'), $arg);
        foreach ($period as $date) {
            $range[] = $date->format($format);
        }

        /* If a period end date was passed to the DatePeriod constructor, it might not
         * be in our results. Not sure if this is a bug or it's just possible because
         * the end date might actually be less than 24 hours away from the previously
         * generated DateTime object, but either way - we have to append it manually.
         */
        if (!is_int($arg) && $range[count($range) - 1] !== $arg->format($format)) {
            $range[] = $arg->format($format);
        }

        return $range;
    }
}
